Backing Yardage Calculator

Get backing yardage for any quilt. It compares horizontal vs. vertical seams, picks the thriftier layout, and adds overhang for longarm or domestic quilting.

How the backing math works

Your backing has to be bigger than the quilt top so there's something to hold onto while you baste and quilt — usually 4 inches past every edge for a longarm. Once the backing is wider than a single width of fabric (about 42″), you have to seam two or more lengths together.

backing size = (width + 2 × overhang) × (length + 2 × overhang)
if wider than the fabric → piece 2+ widths, seam pressed open

Vertical vs. horizontal seams

There are usually two ways to seam a back, and they rarely use the same amount of fabric. The calculator works out both and shows you the thriftier one. Wide-back fabric (108″) can skip the seam entirely — set the usable width to 108 to compare.

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Binding

How much binding fabric do I need?

Open →HST

Backing Yardage Calculator